| Kahale & Martin Racing |
 | |  | |  | |  |
1963 Corvette "Sting Ray" Split Window Coupe
40.77 MPH best pass (1/8 mile) 05/29/2009
.6517 ET (1/8 mile) 05/29//2009
.6517 ET (1/8 mile) 05/29//2009
Since the last posting we have made enough progress with this car to actually enter it in some races.
The addition of two short .062 wire motor bracket braces running from the middle of the motor plate to the
front of the rear pan turned the occasional good pass into consistent performance for the car eliminating
all traces of tire shake. This cost less than a third of a gram in additional weight and didn't stiffen the
chassis much but it did change to point of upward flex forward over and inch. Good enough to take a 5th
last Friday in an 18 car field. Ran right on it's dial in every pass.
While I haven't as yet made a pass on a long track I would expect the ET's to fall in the 1.000 to 1.003
range at roughly 50 to 55 mph. No head turner but a solid car none the less. The mph will be limited by
the motors timing as the break in motor is still in it awaiting my new armatures from BOW. If so that
would make this car .005 quicker which doesn't sound like much progress until you realize it is turning
the same basic numbers with a motor of about 80% of the power even if it is 8 grams lighter over all.
Although I do not like this chassis it has consistently beat the Mercury to the 60 foot but it has taken a
good deal of work to make it so. .1345 is pretty easy. By the way the Mercury is now retired after three
campaigns. Equaling 24 weeks of racing an no less than 300 passes. While it is actually running the
best it ever has I do believe it is a quick as it will ever be in it's current configuration. It is now in the "mule"
category of operation.
We took what we learned for the Mercury and encompassed that acquired knowledge into the Vette. The
dial in of this car then should be much faster. I don't expect it to last as long before we find the next limit
as the last car did.
Current modifications, and yet untested as of 5/28, include dropping the rear body mount some .090".
We have replaced the hollow Slick 7 axle with a solid unit after denting and twisting the hollow one up to
the point I had to cut it out of the car. When I can source one we will go back to the HARD Koford EDM
axles. This is the first part from that team I have been disappointed with. It is also the first catastrophic
failure I have had of any part of my cars. Lowering the body mount has moved 3.3 grams of static weight
to the rear now giving a 32.44/84.50 balance or roughly a 2.7% increase in rear weight distribution, 72.3%
on the back half. The Mercury was 75% back and took less glue to launch. Even a few % can make a
difference. Both cars run on the same tires.
I was going to weight the car up to 120 grams but after several attempts without success abandon the
idea. This car really does have a very shallow draft and I couldn't get the weight where I wanted it to be.
Just no room. Lastly during the body remount it was reconfigured to create something of a friction
damper. Still rattles freely but dampened. Sort of like the old knee action shock absorbers. Total weight
gain after all +/- accounted for about a half gram with most of the axle weight increase coming out with the
body mount.
It has been suggested by Dirk that perhaps my gearing is still a tad tall but I haven't a 58 crown in the box
and will source one or two this weekend to replace the 56.
So what did we change in this car? Lighter weight is the obvious. This chassis was built with lighter
tubing, .072 instead of the .082 and we moved the stiffener from the left side of the car to the right. We
used a chassis wider between main rails and a bit longer wheelie bar. Chassis attitude is 2 degrees
more nose up. Shortened the tire .015". Blind mounted the body work, no advantage other that looks to
this and while still mounted behind the guide post, further forward as a % of wheel base. We built a new
block for the motor using bearings instead of bushings and got a better center on the magnets by
removing the magnet stops from the end bell. Switched to C can hoods and hardware. We learned from
the old motors that the current builds that use narrower tip gaps and taller magnets will tolerate allot
more timing, in fact thrive on it. We started at 25* and are up to 46* without a loss of torque and an
increase of over 10,000 rpm. The end bell was installed +4* so the new arms which were ordered at 46
will be closer to 50*. We also worked hard on bearings, axle, and wheel balance this time around.
Back to the chassis for a minute. There seems to be a correlation between weight distribution front to
back and point of chassis flex. The more static weight I get on the back axle the closer to the motor end of
the chassis I can move the flex point which so far is gaining on the 60 foot times. No way to quantify that
just observations so far. I don't think, as well, there is such a thing as a motor box that is too stiff.
We will, on the next build, be going right back to either JDS or Slick 7 chassis. My one and only build of
these knock off stainless units. I do have some Trash chassis to sort through as well which seem better
than the current one but untested.
By the way, I don't maintain this site for the seasoned veterans of this sport but for the newer guys.
As can be seen from my cars performance, being a solid 1/10 off the pace I'm still on the steep end of
the learning curve myself. As no one flocks to you to give you their speed secrets we're on this
journey together. As I learn, I will continue to pass along what I learn. That said I do and will continue
to make errors and will freely admit to them and correct them as we go. I am not the "last word", just
a dedicated racer.
If you have ideas or topics you would like to cover in the tech section please feel
free to pass them to me at: martyn@tbc.net and well see what we can do.
5/29/2009
A good outing all in all and again set a new best for the car:
60ft .1384
split .4073
1/8 .6517
MPH 40.58 (record above on back up pass.
While the Mercury would lay down an occasional .640 it's normal was .680 ish. The Vette laid down a
long stringer of low .650's and this weeks chassis and body mount modifications we a big help now
running with very little glue. The power continues to get worse week over week at this battery track, ergo
I'm even more pleased with the result as we are down over a volt now and still running quicker week over
week.
Like the idiot I can be on occasion I broke a very basic rule I have. Never change a race set up on race
day. Well I did and hurt myself. Well, almost, I recovered but barely and for my pain was rewarded with a
14% increase in motor power and an additional 45 gr/cm torque with an extra thousand rpm to boot. I
swapped the armature from the Mercury, a Pro Slot 560 38* that actually measures 46* into the new setup
this car was running changing up from the 30* 560 Bow arm I break in new cars on. This is a ball bearing
Parma I built with a slightly advanced end bell so the power increase is over the Mercury motor I had been
campaigning the last few months.
Anyway, when I fit this bell I evidently intersected the lower left (negative) hood hardware mounting
screw with the bell mount screw thus grounding it out. Must have been a paper thin slice of poly there for
quite some time as this bell has been in use nearly a month now with no problem. First pass on the
dyno gave large numbers and a puff of smoke along with burning the hood screw off flush which meant I
had to build a new bell just an hour before leaving for the race.
My normal method is to build and fit the bell even before fitting the magnets so I can fixture it with a can
plug to center the bearing and align the hoods. Well doing that in the blind on a tight fit magnet slug was
as good as it would get and evidently close enough for horseshoes and hand grenades but it took four
runs at it to get it right.
As per usual most of the mid 6 cars on my home track out mph me by 2 or 3 mph but give up .02 or
more to the 60 and use a good deal more glue to get than number. A few months ago it seemed every
one was quite content to build mid to upper 7 cars but now the field is just littered with 6 rides but I've
been able to maintain a .02 advantage so far on the S-16D cars and anyone equal to or quicker is either
Lexan and 20 grams or more lighter OR, as I found out last night running spec 15's and a few single mag
12's. Even my buddy Carl has converted to a spec 15...Traitor :)
06/05/2009
Last night was the end of this sessions 8 week points race in both heats. I entered the first heat in 8th
place after seven weeks of racing and won enough rounds to finish 7th in the points. High enough to
trophy but not "in the money". The second heat was more interesting. I had been 5th going into last week
but slipped to 7th it seemed in just an awful display of poor index selection judgment and driving. At the
beginning of the night it was noted that a racer further down the bracket and out of the top ten was not
awarded his round points properly in week 5 and after the error was corrected propelled him to 6th
kicking be back further to 8th and possibly out of the trophy range if I didn't have a good showing in this
final week.
Round 1 I dial .675 and run .672 breaking out BUT the other driver red lights and I take the round.
Round 2 dial .670 and run a .672 and hit a .04 tree taking the round
Round 3 dial .672 and run .6721 and a .005 tree!! Best round of the night and a stunning win over a very
good car/driver
Round 4 dial back to .665 and a bit of extra care in lane prep. I'm racing the points leader in the final round
who is dialing .720. He's been watching my ladder climb all night taking out already the #2 and 3 guys in
round wins hard. I've had lane choice the first three rounds but he gets it in the finial and puts me in the
left lane where the car has run about .01 quicker during time trials but less consistent trying to rattle me.
He hunts the tree looking for that slight edge and draws the big red eye by - .0003!!!! So no brakes for me
and run a .6559 just to show off and take the race, set low et and first place. Not only do I win the race but
stepping on three guys in front of me going into the last week jumps me from 8th to 3rd place, on the
podium and in the money for my first time ever. Track bucks but part money none the less!! It was a great
night. That is my first podium series showing since 1982 and it felt GREAT!.
The Mercury has set idle for two weeks as I took that motor for the Vette. I loaded the old style Pro Slot
canned 16C which has made pretty fair power but suffers heat related power losses in repetitive rounds if
too close together. I took it as a back up car just in case I shucked a gear in the new set up we put in the
Vette. My suspicions were correct in that this motor performed only on par with my second best S-16D, a
bushing version of the motor in the Vette and .04 slower than the BB version running .680 +/- .015. I also
took my best 16C but never loaded it in either car. I've built three of the 16C's in the last week and find no
edge other than weight compared to the best S-16D's I've built.
The addition of two short .062 wire motor bracket braces running from the middle of the motor plate to the
front of the rear pan turned the occasional good pass into consistent performance for the car eliminating
all traces of tire shake. This cost less than a third of a gram in additional weight and didn't stiffen the
chassis much but it did change to point of upward flex forward over and inch. Good enough to take a 5th
last Friday in an 18 car field. Ran right on it's dial in every pass.
While I haven't as yet made a pass on a long track I would expect the ET's to fall in the 1.000 to 1.003
range at roughly 50 to 55 mph. No head turner but a solid car none the less. The mph will be limited by
the motors timing as the break in motor is still in it awaiting my new armatures from BOW. If so that
would make this car .005 quicker which doesn't sound like much progress until you realize it is turning
the same basic numbers with a motor of about 80% of the power even if it is 8 grams lighter over all.
Although I do not like this chassis it has consistently beat the Mercury to the 60 foot but it has taken a
good deal of work to make it so. .1345 is pretty easy. By the way the Mercury is now retired after three
campaigns. Equaling 24 weeks of racing an no less than 300 passes. While it is actually running the
best it ever has I do believe it is a quick as it will ever be in it's current configuration. It is now in the "mule"
category of operation.
We took what we learned for the Mercury and encompassed that acquired knowledge into the Vette. The
dial in of this car then should be much faster. I don't expect it to last as long before we find the next limit
as the last car did.
Current modifications, and yet untested as of 5/28, include dropping the rear body mount some .090".
We have replaced the hollow Slick 7 axle with a solid unit after denting and twisting the hollow one up to
the point I had to cut it out of the car. When I can source one we will go back to the HARD Koford EDM
axles. This is the first part from that team I have been disappointed with. It is also the first catastrophic
failure I have had of any part of my cars. Lowering the body mount has moved 3.3 grams of static weight
to the rear now giving a 32.44/84.50 balance or roughly a 2.7% increase in rear weight distribution, 72.3%
on the back half. The Mercury was 75% back and took less glue to launch. Even a few % can make a
difference. Both cars run on the same tires.
I was going to weight the car up to 120 grams but after several attempts without success abandon the
idea. This car really does have a very shallow draft and I couldn't get the weight where I wanted it to be.
Just no room. Lastly during the body remount it was reconfigured to create something of a friction
damper. Still rattles freely but dampened. Sort of like the old knee action shock absorbers. Total weight
gain after all +/- accounted for about a half gram with most of the axle weight increase coming out with the
body mount.
It has been suggested by Dirk that perhaps my gearing is still a tad tall but I haven't a 58 crown in the box
and will source one or two this weekend to replace the 56.
So what did we change in this car? Lighter weight is the obvious. This chassis was built with lighter
tubing, .072 instead of the .082 and we moved the stiffener from the left side of the car to the right. We
used a chassis wider between main rails and a bit longer wheelie bar. Chassis attitude is 2 degrees
more nose up. Shortened the tire .015". Blind mounted the body work, no advantage other that looks to
this and while still mounted behind the guide post, further forward as a % of wheel base. We built a new
block for the motor using bearings instead of bushings and got a better center on the magnets by
removing the magnet stops from the end bell. Switched to C can hoods and hardware. We learned from
the old motors that the current builds that use narrower tip gaps and taller magnets will tolerate allot
more timing, in fact thrive on it. We started at 25* and are up to 46* without a loss of torque and an
increase of over 10,000 rpm. The end bell was installed +4* so the new arms which were ordered at 46
will be closer to 50*. We also worked hard on bearings, axle, and wheel balance this time around.
Back to the chassis for a minute. There seems to be a correlation between weight distribution front to
back and point of chassis flex. The more static weight I get on the back axle the closer to the motor end of
the chassis I can move the flex point which so far is gaining on the 60 foot times. No way to quantify that
just observations so far. I don't think, as well, there is such a thing as a motor box that is too stiff.
We will, on the next build, be going right back to either JDS or Slick 7 chassis. My one and only build of
these knock off stainless units. I do have some Trash chassis to sort through as well which seem better
than the current one but untested.
By the way, I don't maintain this site for the seasoned veterans of this sport but for the newer guys.
As can be seen from my cars performance, being a solid 1/10 off the pace I'm still on the steep end of
the learning curve myself. As no one flocks to you to give you their speed secrets we're on this
journey together. As I learn, I will continue to pass along what I learn. That said I do and will continue
to make errors and will freely admit to them and correct them as we go. I am not the "last word", just
a dedicated racer.
If you have ideas or topics you would like to cover in the tech section please feel
free to pass them to me at: martyn@tbc.net and well see what we can do.
5/29/2009
A good outing all in all and again set a new best for the car:
60ft .1384
split .4073
1/8 .6517
MPH 40.58 (record above on back up pass.
While the Mercury would lay down an occasional .640 it's normal was .680 ish. The Vette laid down a
long stringer of low .650's and this weeks chassis and body mount modifications we a big help now
running with very little glue. The power continues to get worse week over week at this battery track, ergo
I'm even more pleased with the result as we are down over a volt now and still running quicker week over
week.
Like the idiot I can be on occasion I broke a very basic rule I have. Never change a race set up on race
day. Well I did and hurt myself. Well, almost, I recovered but barely and for my pain was rewarded with a
14% increase in motor power and an additional 45 gr/cm torque with an extra thousand rpm to boot. I
swapped the armature from the Mercury, a Pro Slot 560 38* that actually measures 46* into the new setup
this car was running changing up from the 30* 560 Bow arm I break in new cars on. This is a ball bearing
Parma I built with a slightly advanced end bell so the power increase is over the Mercury motor I had been
campaigning the last few months.
Anyway, when I fit this bell I evidently intersected the lower left (negative) hood hardware mounting
screw with the bell mount screw thus grounding it out. Must have been a paper thin slice of poly there for
quite some time as this bell has been in use nearly a month now with no problem. First pass on the
dyno gave large numbers and a puff of smoke along with burning the hood screw off flush which meant I
had to build a new bell just an hour before leaving for the race.
My normal method is to build and fit the bell even before fitting the magnets so I can fixture it with a can
plug to center the bearing and align the hoods. Well doing that in the blind on a tight fit magnet slug was
as good as it would get and evidently close enough for horseshoes and hand grenades but it took four
runs at it to get it right.
As per usual most of the mid 6 cars on my home track out mph me by 2 or 3 mph but give up .02 or
more to the 60 and use a good deal more glue to get than number. A few months ago it seemed every
one was quite content to build mid to upper 7 cars but now the field is just littered with 6 rides but I've
been able to maintain a .02 advantage so far on the S-16D cars and anyone equal to or quicker is either
Lexan and 20 grams or more lighter OR, as I found out last night running spec 15's and a few single mag
12's. Even my buddy Carl has converted to a spec 15...Traitor :)
06/05/2009
Last night was the end of this sessions 8 week points race in both heats. I entered the first heat in 8th
place after seven weeks of racing and won enough rounds to finish 7th in the points. High enough to
trophy but not "in the money". The second heat was more interesting. I had been 5th going into last week
but slipped to 7th it seemed in just an awful display of poor index selection judgment and driving. At the
beginning of the night it was noted that a racer further down the bracket and out of the top ten was not
awarded his round points properly in week 5 and after the error was corrected propelled him to 6th
kicking be back further to 8th and possibly out of the trophy range if I didn't have a good showing in this
final week.
Round 1 I dial .675 and run .672 breaking out BUT the other driver red lights and I take the round.
Round 2 dial .670 and run a .672 and hit a .04 tree taking the round
Round 3 dial .672 and run .6721 and a .005 tree!! Best round of the night and a stunning win over a very
good car/driver
Round 4 dial back to .665 and a bit of extra care in lane prep. I'm racing the points leader in the final round
who is dialing .720. He's been watching my ladder climb all night taking out already the #2 and 3 guys in
round wins hard. I've had lane choice the first three rounds but he gets it in the finial and puts me in the
left lane where the car has run about .01 quicker during time trials but less consistent trying to rattle me.
He hunts the tree looking for that slight edge and draws the big red eye by - .0003!!!! So no brakes for me
and run a .6559 just to show off and take the race, set low et and first place. Not only do I win the race but
stepping on three guys in front of me going into the last week jumps me from 8th to 3rd place, on the
podium and in the money for my first time ever. Track bucks but part money none the less!! It was a great
night. That is my first podium series showing since 1982 and it felt GREAT!.
The Mercury has set idle for two weeks as I took that motor for the Vette. I loaded the old style Pro Slot
canned 16C which has made pretty fair power but suffers heat related power losses in repetitive rounds if
too close together. I took it as a back up car just in case I shucked a gear in the new set up we put in the
Vette. My suspicions were correct in that this motor performed only on par with my second best S-16D, a
bushing version of the motor in the Vette and .04 slower than the BB version running .680 +/- .015. I also
took my best 16C but never loaded it in either car. I've built three of the 16C's in the last week and find no
edge other than weight compared to the best S-16D's I've built.